20154256642 has 8 divisors (see below), whose sum is σ = 32556876156. Its totient is φ = 9301964592.

The previous prime is 20154256613. The next prime is 20154256651. The reversal of 20154256642 is 24665245102.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19435426921 + 718829721 = 139411^2 + 26811^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×20154256642² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 387581833 + ... + 387581884.

Almost surely, 2^20154256642 is an apocalyptic number.

20154256642 is a deficient number, since it is larger than the sum of its proper divisors (12402619514).

20154256642 is a wasteful number, since it uses less digits than its factorization.

20154256642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 775163732.

The product of its (nonzero) digits is 115200, while the sum is 37.

The spelling of 20154256642 in words is "twenty billion, one hundred fifty-four million, two hundred fifty-six thousand, six hundred forty-two".